In numerous commercial and industrial coating and coating-related applications there inherently exists a need for significant improvement in the nature of the products produced thereby and the manufacturing processes or treatments utilized in producing the same, with a view towards enhanced results, lowered costs, avoidance of industrial hazards, and compliance with environmental safeguards.
Thus, in various commercial and industrial applications, diverse coating, laminating, adhesive-applying, labelling, and printing operations are performed which quite frequently utilize carriers, vehicles, solvents or the like which carry environmental hazards all of excess volatility, flammability, and indeed even presence of carcinogens, among other deleterious aspects. Thus, one of the most widely-used such coatings to enhance multicolor printing by high sheen or gloss and to provide a measure of wear protection utilizes nitrocellulose carried in an acetone solvent.
Heretofore, it has been conventional and indeed necessary in the printing arts in high resolution color printing, rotogravure and the like, especially for high gloss products as advertising literature, display advertising, high publication covers and the like, to seek to enhance, protect, and preserve the printed web, as a color printed web in a Cerruti press, by the coating of the printed matter with an acetone solution of nitrocellulose. Such coating is conventional and widely used throughout the paper and printing industry, and features quite low relative cost heretofore. Nitrocellulose and like related coatings, however, can be difficult to handle by virtue of volatility and flammability characteristics requiring careful handling in the necessary effort to impart a protective finish to printed matter. Conventionally, nitrocellulose coatings are carried in a acetone solvent which require careful drying after application and wherein indeed application as by rollers of the like is difficult due to a clinging nature of the nitrocellulose to the roller.
In addition thereto, there follows the unavoidable environmental hazards of organic solvents which are highly undesirable and indeed by increasing regulation from the EPA as well as other Federal and State authorities calls for increased care and expense in the use, handling, and recovery pretreatment of the same.
While such coatings do provide the necessary and desirable high gloss or reflectivity, the same are not sturdy or durable under exposed or extended wear conditions, with quickly developing cracks or other degradation of the reflectance, all resulting in a product not especially desirable to advertisers and printers on any basis other than very low cost. To the durability problem must be added the increasing economic burden, both in capital equipment and operating expense, of compliance with environmental regulation, principally as to containment and recovery of the organic acetone vehicle, thereby increasing the previously relatively low costs.
Another technique widely employed in providing protective coatings on printed material as may be needed for high visibility and adverse wear conditions, and which avoids the hazards and difficulties of nitrocellulose coatings, is the lamination of a separate protective web of polymeric material over the printed stock. While providing good wear protection and avoiding the difficulties of nitrocellulose coatings, several disadvantages manifest themselves, including the entire separate and major manipulative step of effecting a two-web lamination operation, with necessary additional equipment. Further, the overlay of a separate polymeric web, while quite transparent, nonetheless is incapable of imparting a high gloss to the finished article. Thus, while a highly desired gloss or reflectivity reading on a standard reflectometer in the printing industry might be on the order of 90 or above, laminated web readings may ordinarily be found much lower, as 73 or 74, a substantial diminution in eye-catching appeal. For this reason, except where virtually prohibited, nitrocellulose coatings have hitherto remained preferred.
Efforts are continuously underway to find some manner of avoiding such problems and wherein a common approach has been to seek to utilize a water-based coating vehicle or the like. Such efforts heretofore in providing aqueous carriers, however, have not been successful, including difficulty of manipulation, unsuitablity for the substrate or environment with which the same are associated, drying difficulties, poor resultant products, as well as in many cases a necessity of completely altering the equipment required with resultant unwanted capital expense and the unavoidable discard of perfectly ably functioning existing equipment.
There is, therefore, a major need for an improvement in this area of industrial activity.
While improved high gloss, durable, easily curable coatings for printed stock are major area of interest, collaterally thereto, there is companion interest in and need for high gloss printing inks, per se, which similarly avoid environmental and equipment problems, while yet providing an enhanced, bright ink image. Again, if feasible, water-base inks avoiding volatility, flammability, and organic solvent concerns are extremely desirable.